<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>grep - Perldoc Browser</title>
    <link rel="search" href="https://perldoc.perl.org/opensearch.xml" type="application/opensearchdescription+xml" title="Perldoc Browser">
    <link rel="canonical" href="https://perldoc.perl.org/functions/grep">
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" integrity="sha384-JcKb8q3iqJ61gNV9KGb8thSsNjpSL0n8PARn9HuZOnIxN0hoP+VmmDGMN5t9UJ0Z" crossorigin="anonymous">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/10.5.0/styles/stackoverflow-light.min.css" integrity="sha512-cG1IdFxqipi3gqLmksLtuk13C+hBa57a6zpWxMeoY3Q9O6ooFxq50DayCdm0QrDgZjMUn23z/0PMZlgft7Yp5Q==" crossorigin="anonymous" />
    <style>
      body {
        background: #f4f4f5;
        color: #020202;
      }
      .navbar-dark {
        background-image: -webkit-linear-gradient(top, #005f85 0, #002e49 100%);
        background-image: -o-linear-gradient(top, #005f85 0, #002e49 100%);
        background-image: linear-gradient(to bottom, #005f85 0, #002e49 100%);
        filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ff005f85', endColorstr='#ff002e49', GradientType=0);
        background-repeat: repeat-x;
      }
      .navbar-dark .navbar-nav .nav-link,
      .navbar-dark .navbar-nav .nav-link:focus { color: #fff }
      .navbar-dark .navbar-nav .nav-link:hover { color: #ffef68 }
      #wrapperlicious {
        margin: 0 auto;
        font: 0.9em 'Helvetica Neue', Helvetica, sans-serif;
        font-weight: normal;
        line-height: 1.5em;
        margin: 0;
        padding: 0;
      }
      #wrapperlicious h1 { font-size: 1.5em }
      #wrapperlicious h2 { font-size: 1.3em }
      #wrapperlicious h3 { font-size: 1.1em }
      #wrapperlicious h4 { font-size: 0.9em }
      #wrapperlicious h1, #wrapperlicious h2, #wrapperlicious h3,
      #wrapperlicious h4, #wrapperlicious dt {
        color: #020202;
        margin-top: 1em;
        margin-bottom: 1em;
        position: relative;
        font-weight: bold;
      }
      #wrapperlicious a { color: inherit; text-decoration: underline }
      #wrapperlicious #toc { text-decoration: none }
      #wrapperlicious a:hover { color: #2a2a2a }
      #wrapperlicious a img { border: 0 }
      #wrapperlicious :not(pre) > code {
        color: inherit;
        background-color: rgba(0, 0, 0, 0.04);
        border-radius: 3px;
        font: 0.9em Consolas, Menlo, Monaco, monospace;
        padding: 0.3em;
      }
      #wrapperlicious dd {
        margin: 0;
        margin-left: 2em;
      }
      #wrapperlicious dt {
        color: #2a2a2a;
        font-weight: bold;
        margin-left: 0.9em;
      }
      #wrapperlicious p {
        margin-bottom: 1em;
        margin-top: 1em;
      }
      #wrapperlicious li > p {
        margin-bottom: 0;
        margin-top: 0;
      }
      #wrapperlicious pre {
        border: 1px solid #c1c1c1;
        border-radius: 3px;
        font: 100% Consolas, Menlo, Monaco, monospace;
        margin-bottom: 1em;
        margin-top: 1em;
      }
      #wrapperlicious pre > code {
        display: block;
        background-color: #f6f6f6;
        font: 0.9em Consolas, Menlo, Monaco, monospace;
        line-height: 1.5em;
        text-align: left;
        white-space: pre;
        padding: 1em;
      }
      #wrapperlicious dl, #wrapperlicious ol, #wrapperlicious ul {
        margin-bottom: 1em;
        margin-top: 1em;
      }
      #wrapperlicious ul {
        list-style-type: square;
      }
      #wrapperlicious ul ul {
        margin-bottom: 0px;
        margin-top: 0px;
      }
      #footer {
        font-size: 0.8em;
        padding-top: 0.5em;
        text-align: center;
      }
      #more {
        display: inline;
        font-size: 0.8em;
      }
      #perldocdiv {
        background-color: #fff;
        border: 1px solid #c1c1c1;
        border-bottom-left-radius: 5px;
        border-bottom-right-radius: 5px;
        margin-left: auto;
        margin-right: auto;
        padding: 3em;
        padding-top: 1em;
        max-width: 960px;
      }
      #moduleversion { float: right }
      #wrapperlicious .leading-notice {
        font-style: italic;
        padding-left: 1em;
        margin-top: 1em;
        margin-bottom: 1em;
      }
      #wrapperlicious .permalink {
        display: none;
        left: -0.75em;
        position: absolute;
        padding-right: 0.25em;
        text-decoration: none;
      }
      #wrapperlicious h1:hover .permalink, #wrapperlicious h2:hover .permalink,
      #wrapperlicious h3:hover .permalink, #wrapperlicious h4:hover .permalink,
      #wrapperlicious dt:hover .permalink {
        display: block;
      }
    </style>
    <!-- Global site tag (gtag.js) - Google Analytics -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=G-KVNWBNT5FB"></script>
    <script>
      window.dataLayer = window.dataLayer || [];
      function gtag(){dataLayer.push(arguments);}
      gtag('js', new Date());

      gtag('config', 'G-KVNWBNT5FB');
      gtag('config', 'UA-50555-3');
    </script>
  </head>
  <body>
    <nav class="navbar navbar-expand-md navbar-dark bg-dark justify-content-between">
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <a class="navbar-brand" href="https://perldoc.perl.org/">Perldoc Browser</a>
  <div class="collapse navbar-collapse" id="navbarNav">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item dropdown text-nowrap">
        <a class="nav-link dropdown-toggle" href="grep.html#" id="dropdownlink-stable" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">5.35.0</a>
        <div class="dropdown-menu" aria-labelledby="dropdownlink-stable">
          <a class="dropdown-item" href="https://perldoc.perl.org/functions/grep">Latest</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.38.2/functions/grep">5.38.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.38.1/functions/grep">5.38.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.38.0/functions/grep">5.38.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.36.3/functions/grep">5.36.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.36.2/functions/grep">5.36.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.36.1/functions/grep">5.36.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.36.0/functions/grep">5.36.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.34.3/functions/grep">5.34.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.34.2/functions/grep">5.34.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.34.1/functions/grep">5.34.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.34.0/functions/grep">5.34.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.32.1/functions/grep">5.32.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.32.0/functions/grep">5.32.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.30.3/functions/grep">5.30.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.30.2/functions/grep">5.30.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.30.1/functions/grep">5.30.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.30.0/functions/grep">5.30.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.28.3/functions/grep">5.28.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.28.2/functions/grep">5.28.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.28.1/functions/grep">5.28.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.28.0/functions/grep">5.28.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.26.3/functions/grep">5.26.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.26.2/functions/grep">5.26.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.26.1/functions/grep">5.26.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.26.0/functions/grep">5.26.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.24.4/functions/grep">5.24.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.24.3/functions/grep">5.24.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.24.2/functions/grep">5.24.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.24.1/functions/grep">5.24.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.24.0/functions/grep">5.24.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.22.4/functions/grep">5.22.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.22.3/functions/grep">5.22.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.22.2/functions/grep">5.22.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.22.1/functions/grep">5.22.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.22.0/functions/grep">5.22.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.20.3/functions/grep">5.20.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.20.2/functions/grep">5.20.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.20.1/functions/grep">5.20.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.20.0/functions/grep">5.20.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.18.4/functions/grep">5.18.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.18.3/functions/grep">5.18.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.18.2/functions/grep">5.18.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.18.1/functions/grep">5.18.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.18.0/functions/grep">5.18.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.16.3/functions/grep">5.16.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.16.2/functions/grep">5.16.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.16.1/functions/grep">5.16.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.16.0/functions/grep">5.16.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.14.4/functions/grep">5.14.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.14.3/functions/grep">5.14.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.14.2/functions/grep">5.14.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.14.1/functions/grep">5.14.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.14.0/functions/grep">5.14.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.12.5/functions/grep">5.12.5</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.12.4/functions/grep">5.12.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.12.3/functions/grep">5.12.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.12.2/functions/grep">5.12.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.12.1/functions/grep">5.12.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.12.0/functions/grep">5.12.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.10.1/functions/grep">5.10.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.10.0/functions/grep">5.10.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.9/functions/grep">5.8.9</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.8/functions/grep">5.8.8</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.7/functions/grep">5.8.7</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.6/functions/grep">5.8.6</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.5/functions/grep">5.8.5</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.4/functions/grep">5.8.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.3/functions/grep">5.8.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.2/functions/grep">5.8.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.1/functions/grep">5.8.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.8.0/functions/grep">5.8.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.6.2/functions/grep">5.6.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.6.1/functions/grep">5.6.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.6.0/functions/grep">5.6.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.005_04/functions/grep">5.005_04</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.005_03/functions/grep">5.005_03</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.005_02/functions/grep">5.005_02</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.005_01/functions/grep">5.005_01</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.005/functions/grep">5.005</a>
        </div>
      </li>
      <li class="nav-item dropdown text-nowrap">
        <a class="nav-link dropdown-toggle" href="grep.html#" id="dropdownlink-dev" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Dev</a>
        <div class="dropdown-menu" aria-labelledby="dropdownlink-dev">
          <a class="dropdown-item" href="https://perldoc.perl.org/blead/functions/grep">blead</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.39.6/functions/grep">5.39.6</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.39.5/functions/grep">5.39.5</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.39.4/functions/grep">5.39.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.39.3/functions/grep">5.39.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.39.2/functions/grep">5.39.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.39.1/functions/grep">5.39.1</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.38.0-RC2/functions/grep">5.38.0-RC2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.38.0-RC1/functions/grep">5.38.0-RC1</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.11/functions/grep">5.37.11</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.10/functions/grep">5.37.10</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.9/functions/grep">5.37.9</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.8/functions/grep">5.37.8</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.7/functions/grep">5.37.7</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.6/functions/grep">5.37.6</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.5/functions/grep">5.37.5</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.4/functions/grep">5.37.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.3/functions/grep">5.37.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.2/functions/grep">5.37.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.1/functions/grep">5.37.1</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.37.0/functions/grep">5.37.0</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.11/functions/grep">5.35.11</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.10/functions/grep">5.35.10</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.9/functions/grep">5.35.9</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.8/functions/grep">5.35.8</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.7/functions/grep">5.35.7</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.6/functions/grep">5.35.6</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.5/functions/grep">5.35.5</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.4/functions/grep">5.35.4</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.3/functions/grep">5.35.3</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.2/functions/grep">5.35.2</a>
          <a class="dropdown-item" href="https://perldoc.perl.org/5.35.1/functions/grep">5.35.1</a>
          <a class="dropdown-item active" href="grep.html">5.35.0</a>
        </div>
      </li>
      <li class="nav-item dropdown text-nowrap">
        <a class="nav-link dropdown-toggle" href="grep.html#" id="dropdownlink-nav" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Documentation</a>
        <div class="dropdown-menu" aria-labelledby="dropdownlink-nav">
          <a class="dropdown-item" href="../perl.html">Perl</a>
          <a class="dropdown-item" href="../perlintro.html">Intro</a>
          <a class="dropdown-item" href="../perl.html#Tutorials">Tutorials</a>
          <a class="dropdown-item" href="../perlfaq.html">FAQs</a>
          <a class="dropdown-item" href="../perl.html#Reference-Manual">Reference</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="../perlop.html">Operators</a>
          <a class="dropdown-item" href="../functions.html">Functions</a>
          <a class="dropdown-item" href="../variables.html">Variables</a>
          <a class="dropdown-item" href="../modules.html">Modules</a>
          <a class="dropdown-item" href="../perlutil.html">Utilities</a>
          <div class="dropdown-divider"></div>
          <a class="dropdown-item" href="../perlcommunity.html">Community</a>
          <a class="dropdown-item" href="../perlhist.html">History</a>
        </div>
      </li>
    </ul>
    <ul class="navbar-nav">
      <script>
        function set_expand (expand) {
          var perldocdiv = document.getElementById('perldocdiv');
          var width = window.getComputedStyle(perldocdiv).getPropertyValue('max-width');
          var expanded = (width == '' || width == 'none') ? true : false;
          if (expand === null) {
            expand = !expanded;
          }
          if ((expand && !expanded) || (!expand && expanded)) {
            perldocdiv.style.setProperty('max-width', expand ? 'none' : '960px');
            var button_classlist = document.getElementById('content-expand-button').classList;
            if (expand) {
              button_classlist.add('btn-light');
              button_classlist.remove('btn-outline-light');
            } else {
              button_classlist.add('btn-outline-light');
              button_classlist.remove('btn-light');
            }
          }
          return expand;
        }
        function toggle_expand () {
          var expand = set_expand(null);
          document.cookie = 'perldoc_expand=' + (expand ? 1 : 0) + '; path=/; expires=Tue, 19 Jan 2038 03:14:07 UTC';
        }
        function read_expand () {
          return document.cookie.split(';').some(function (item) { return item.indexOf('perldoc_expand=1') >= 0 });
        }
        if (document.readyState === 'loading') {
          document.addEventListener('DOMContentLoaded', function () {
            if (read_expand()) {
              set_expand(true);
            }
          });
        } else if (read_expand()) {
          set_expand(true);
        }
      </script>
      <button id="content-expand-button" type="button" class="btn btn-outline-light d-none d-lg-inline-block mr-2" onclick="toggle_expand()">Expand</button>
    <ul>
    <form class="form-inline" method="get" action="https://perldoc.perl.org/5.35.0/search">
      <input class="form-control mr-3" type="search" name="q" placeholder="Search" aria-label="Search">
    </form>
  </div>
</nav>

    <div id="wrapperlicious" class="container-fluid">
      <div id="perldocdiv">
        <div id="links">
          <a href="../functions.html">functions</a>
            / <a href="grep.html">grep</a>
          <div id="more">
            (<a href="grep.txt">source</a>,
            <a href="CORE.html#grep-BLOCK-LIST">CPAN</a>)
          </div>
        </div>
        <div class="leading-notice">
          You are viewing the version of this documentation from Perl 5.35.0.
            This is a development version of Perl.
        </div>
      <dl>

<dt id="grep-BLOCK-LIST"><a class="permalink" href="grep.html#grep-BLOCK-LIST">#</a><a id="grep"></a>grep BLOCK LIST </dt>
<dd>

</dd>
<dt id="grep-EXPR,LIST"><a class="permalink" href="grep.html#grep-EXPR,LIST">#</a><a id="grep1"></a><a id="grep-EXPR-LIST"></a>grep EXPR,LIST</dt>
<dd>

<p>This is similar in spirit to, but not the same as, <a href="http://man.he.net/man1/grep">grep(1)</a> and its relatives. In particular, it is not limited to using regular expressions.</p>

<p>Evaluates the BLOCK or EXPR for each element of LIST (locally setting <a href="../perlvar.html#%24_"><code>$_</code></a> to each element) and returns the list value consisting of those elements for which the expression evaluated to true. In scalar context, returns the number of times the expression was true.</p>

<pre><code>my @foo = grep(!/^#/, @bar);    # weed out comments</code></pre>

<p>or equivalently,</p>

<pre><code>my @foo = grep {!/^#/} @bar;    # weed out comments</code></pre>

<p>Note that <a href="../perlvar.html#%24_"><code>$_</code></a> is an alias to the list value, so it can be used to modify the elements of the LIST. While this is useful and supported, it can cause bizarre results if the elements of LIST are not variables. Similarly, grep returns aliases into the original list, much as a for loop&#39;s index variable aliases the list elements. That is, modifying an element of a list returned by grep (for example, in a <code>foreach</code>, <a href="map.html"><code>map</code></a> or another <a href="grep.html"><code>grep</code></a>) actually modifies the element in the original list. This is usually something to be avoided when writing clear code.</p>

<p>See also <a href="map.html"><code>map</code></a> for a list composed of the results of the BLOCK or EXPR.</p>

</dd>
</dl>


      </div>
      <div id="footer">
        <p>Perldoc Browser is maintained by Dan Book (<a href="https://metacpan.org/author/DBOOK">DBOOK</a>). Please contact him via the <a href="https://github.com/Grinnz/perldoc-browser/issues">GitHub issue tracker</a> or <a href="mailto:dbook@cpan.org">email</a> regarding any issues with the site itself, search, or rendering of documentation.</p>

<p>The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. Please contact them via the <a href="https://github.com/Perl/perl5/issues">Perl issue tracker</a>, the <a href="https://lists.perl.org/list/perl5-porters.html">mailing list</a>, or <a href="https://kiwiirc.com/client/irc.perl.org/p5p">IRC</a> to report any issues with the contents or format of the documentation.</p>


      </div>
    </div>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.slim.min.js" integrity="sha512-/DXTXr6nQodMUiq+IUJYCt2PPOUjrHJ9wFrqpJ3XkgPNOZVfMok7cRw6CSxyCQxXn6ozlESsSh1/sMCTF1rL/g==" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.1/umd/popper.min.js" integrity="sha512-ubuT8Z88WxezgSqf3RLuNi5lmjstiJcyezx34yIU2gAHonIi27Na7atqzUZCOoY4CExaoFumzOsFQ2Ch+I/HCw==" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js" integrity="sha384-B4gt1jrGC7Jh4AgTPSdUtOBvfO8shuf57BaghqFfPlYxofvL8/KUEfYiJOMMV+rV" crossorigin="anonymous"></script>
    <script src="../../highlight.pack.js"></script>
    <script>hljs.highlightAll();</script>
  </body>
</html>
